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FFmpeg/libavcodec/alsdec.c

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  1. /*

  2.  * MPEG-4 ALS decoder

  3.  * Copyright (c) 2009 Thilo Borgmann <thilo.borgmann _at_ googlemail.com>

  4.  *

  5.  * This file is part of Libav.

  6.  *

  7.  * Libav is free software; you can redistribute it and/or

  8.  * modify it under the terms of the GNU Lesser General Public

  9.  * License as published by the Free Software Foundation; either

  10.  * version 2.1 of the License, or (at your option) any later version.

  11.  *

  12.  * Libav is distributed in the hope that it will be useful,

  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

  15.  * Lesser General Public License for more details.

  16.  *

  17.  * You should have received a copy of the GNU Lesser General Public

  18.  * License along with Libav; if not, write to the Free Software

  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  20.  */

  21. 

  22. /**

  23.  * @file

  24.  * MPEG-4 ALS decoder

  25.  * @author Thilo Borgmann <thilo.borgmann _at_ googlemail.com>

  26.  */

  27. 

  28. #include <inttypes.h>

  29. 

  30. #include "avcodec.h"

  31. #include "get_bits.h"

  32. #include "unary.h"

  33. #include "mpeg4audio.h"

  34. #include "bytestream.h"

  35. #include "bgmc.h"

  36. #include "bswapdsp.h"

  37. #include "internal.h"

  38. #include "libavutil/samplefmt.h"

  39. #include "libavutil/crc.h"

  40. 

  41. #include <stdint.h>

  42. 

  43. /** Rice parameters and corresponding index offsets for decoding the

  44.  *  indices of scaled PARCOR values. The table chosen is set globally

  45.  *  by the encoder and stored in ALSSpecificConfig.

  46.  */

  47. static const int8_t parcor_rice_table[3][20][2] = {

  48.     { {-52, 4}, {-29, 5}, {-31, 4}, { 19, 4}, {-16, 4},

  49.       { 12, 3}, { -7, 3}, {  9, 3}, { -5, 3}, {  6, 3},

  50.       { -4, 3}, {  3, 3}, { -3, 2}, {  3, 2}, { -2, 2},

  51.       {  3, 2}, { -1, 2}, {  2, 2}, { -1, 2}, {  2, 2} },

  52.     { {-58, 3}, {-42, 4}, {-46, 4}, { 37, 5}, {-36, 4},

  53.       { 29, 4}, {-29, 4}, { 25, 4}, {-23, 4}, { 20, 4},

  54.       {-17, 4}, { 16, 4}, {-12, 4}, { 12, 3}, {-10, 4},

  55.       {  7, 3}, { -4, 4}, {  3, 3}, { -1, 3}, {  1, 3} },

  56.     { {-59, 3}, {-45, 5}, {-50, 4}, { 38, 4}, {-39, 4},

  57.       { 32, 4}, {-30, 4}, { 25, 3}, {-23, 3}, { 20, 3},

  58.       {-20, 3}, { 16, 3}, {-13, 3}, { 10, 3}, { -7, 3},

  59.       {  3, 3}, {  0, 3}, { -1, 3}, {  2, 3}, { -1, 2} }

  60. };

  61. 

  62. 

  63. /** Scaled PARCOR values used for the first two PARCOR coefficients.

  64.  *  To be indexed by the Rice coded indices.

  65.  *  Generated by: parcor_scaled_values[i] = 32 + ((i * (i+1)) << 7) - (1 << 20)

  66.  *  Actual values are divided by 32 in order to be stored in 16 bits.

  67.  */

  68. static const int16_t parcor_scaled_values[] = {

  69.     -1048544 / 32, -1048288 / 32, -1047776 / 32, -1047008 / 32,

  70.     -1045984 / 32, -1044704 / 32, -1043168 / 32, -1041376 / 32,

  71.     -1039328 / 32, -1037024 / 32, -1034464 / 32, -1031648 / 32,

  72.     -1028576 / 32, -1025248 / 32, -1021664 / 32, -1017824 / 32,

  73.     -1013728 / 32, -1009376 / 32, -1004768 / 32,  -999904 / 32,

  74.      -994784 / 32,  -989408 / 32,  -983776 / 32,  -977888 / 32,

  75.      -971744 / 32,  -965344 / 32,  -958688 / 32,  -951776 / 32,

  76.      -944608 / 32,  -937184 / 32,  -929504 / 32,  -921568 / 32,

  77.      -913376 / 32,  -904928 / 32,  -896224 / 32,  -887264 / 32,

  78.      -878048 / 32,  -868576 / 32,  -858848 / 32,  -848864 / 32,

  79.      -838624 / 32,  -828128 / 32,  -817376 / 32,  -806368 / 32,

  80.      -795104 / 32,  -783584 / 32,  -771808 / 32,  -759776 / 32,

  81.      -747488 / 32,  -734944 / 32,  -722144 / 32,  -709088 / 32,

  82.      -695776 / 32,  -682208 / 32,  -668384 / 32,  -654304 / 32,

  83.      -639968 / 32,  -625376 / 32,  -610528 / 32,  -595424 / 32,

  84.      -580064 / 32,  -564448 / 32,  -548576 / 32,  -532448 / 32,

  85.      -516064 / 32,  -499424 / 32,  -482528 / 32,  -465376 / 32,

  86.      -447968 / 32,  -430304 / 32,  -412384 / 32,  -394208 / 32,

  87.      -375776 / 32,  -357088 / 32,  -338144 / 32,  -318944 / 32,

  88.      -299488 / 32,  -279776 / 32,  -259808 / 32,  -239584 / 32,

  89.      -219104 / 32,  -198368 / 32,  -177376 / 32,  -156128 / 32,

  90.      -134624 / 32,  -112864 / 32,   -90848 / 32,   -68576 / 32,

  91.       -46048 / 32,   -23264 / 32,     -224 / 32,    23072 / 32,

  92.        46624 / 32,    70432 / 32,    94496 / 32,   118816 / 32,

  93.       143392 / 32,   168224 / 32,   193312 / 32,   218656 / 32,

  94.       244256 / 32,   270112 / 32,   296224 / 32,   322592 / 32,

  95.       349216 / 32,   376096 / 32,   403232 / 32,   430624 / 32,

  96.       458272 / 32,   486176 / 32,   514336 / 32,   542752 / 32,

  97.       571424 / 32,   600352 / 32,   629536 / 32,   658976 / 32,

  98.       688672 / 32,   718624 / 32,   748832 / 32,   779296 / 32,

  99.       810016 / 32,   840992 / 32,   872224 / 32,   903712 / 32,

  100.       935456 / 32,   967456 / 32,   999712 / 32,  1032224 / 32

  101. };

  102. 

  103. 

  104. /** Gain values of p(0) for long-term prediction.

  105.  *  To be indexed by the Rice coded indices.

  106.  */

  107. static const uint8_t ltp_gain_values [4][4] = {

  108.     { 0,  8, 16,  24},

  109.     {32, 40, 48,  56},

  110.     {64, 70, 76,  82},

  111.     {88, 92, 96, 100}

  112. };

  113. 

  114. 

  115. /** Inter-channel weighting factors for multi-channel correlation.

  116.  *  To be indexed by the Rice coded indices.

  117.  */

  118. static const int16_t mcc_weightings[] = {

  119.     204,  192,  179,  166,  153,  140,  128,  115,

  120.     102,   89,   76,   64,   51,   38,   25,   12,

  121.       0,  -12,  -25,  -38,  -51,  -64,  -76,  -89,

  122.    -102, -115, -128, -140, -153, -166, -179, -192

  123. };

  124. 

  125. 

  126. /** Tail codes used in arithmetic coding using block Gilbert-Moore codes.

  127.  */

  128. static const uint8_t tail_code[16][6] = {

  129.     { 74, 44, 25, 13,  7, 3},

  130.     { 68, 42, 24, 13,  7, 3},

  131.     { 58, 39, 23, 13,  7, 3},

  132.     {126, 70, 37, 19, 10, 5},

  133.     {132, 70, 37, 20, 10, 5},

  134.     {124, 70, 38, 20, 10, 5},

  135.     {120, 69, 37, 20, 11, 5},

  136.     {116, 67, 37, 20, 11, 5},

  137.     {108, 66, 36, 20, 10, 5},

  138.     {102, 62, 36, 20, 10, 5},

  139.     { 88, 58, 34, 19, 10, 5},

  140.     {162, 89, 49, 25, 13, 7},

  141.     {156, 87, 49, 26, 14, 7},

  142.     {150, 86, 47, 26, 14, 7},

  143.     {142, 84, 47, 26, 14, 7},

  144.     {131, 79, 46, 26, 14, 7}

  145. };

  146. 

  147. 

  148. enum RA_Flag {

  149.     RA_FLAG_NONE,

  150.     RA_FLAG_FRAMES,

  151.     RA_FLAG_HEADER

  152. };

  153. 

  154. 

  155. typedef struct ALSSpecificConfig {

  156.     uint32_t samples;         ///< number of samples, 0xFFFFFFFF if unknown

  157.     int resolution;           ///< 000 = 8-bit; 001 = 16-bit; 010 = 24-bit; 011 = 32-bit

  158.     int floating;             ///< 1 = IEEE 32-bit floating-point, 0 = integer

  159.     int msb_first;            ///< 1 = original CRC calculated on big-endian system, 0 = little-endian

  160.     int frame_length;         ///< frame length for each frame (last frame may differ)

  161.     int ra_distance;          ///< distance between RA frames (in frames, 0...255)

  162.     enum RA_Flag ra_flag;     ///< indicates where the size of ra units is stored

  163.     int adapt_order;          ///< adaptive order: 1 = on, 0 = off

  164.     int coef_table;           ///< table index of Rice code parameters

  165.     int long_term_prediction; ///< long term prediction (LTP): 1 = on, 0 = off

  166.     int max_order;            ///< maximum prediction order (0..1023)

  167.     int block_switching;      ///< number of block switching levels

  168.     int bgmc;                 ///< "Block Gilbert-Moore Code": 1 = on, 0 = off (Rice coding only)

  169.     int sb_part;              ///< sub-block partition

  170.     int joint_stereo;         ///< joint stereo: 1 = on, 0 = off

  171.     int mc_coding;            ///< extended inter-channel coding (multi channel coding): 1 = on, 0 = off

  172.     int chan_config;          ///< indicates that a chan_config_info field is present

  173.     int chan_sort;            ///< channel rearrangement: 1 = on, 0 = off

  174.     int rlslms;               ///< use "Recursive Least Square-Least Mean Square" predictor: 1 = on, 0 = off

  175.     int chan_config_info;     ///< mapping of channels to loudspeaker locations. Unused until setting channel configuration is implemented.

  176.     int *chan_pos;            ///< original channel positions

  177.     int crc_enabled;          ///< enable Cyclic Redundancy Checksum

  178. } ALSSpecificConfig;

  179. 

  180. 

  181. typedef struct ALSChannelData {

  182.     int stop_flag;

  183.     int master_channel;

  184.     int time_diff_flag;

  185.     int time_diff_sign;

  186.     int time_diff_index;

  187.     int weighting[6];

  188. } ALSChannelData;

  189. 

  190. 

  191. typedef struct ALSDecContext {

  192.     AVCodecContext *avctx;

  193.     ALSSpecificConfig sconf;

  194.     GetBitContext gb;

  195.     BswapDSPContext bdsp;

  196.     const AVCRC *crc_table;

  197.     uint32_t crc_org;               ///< CRC value of the original input data

  198.     uint32_t crc;                   ///< CRC value calculated from decoded data

  199.     unsigned int cur_frame_length;  ///< length of the current frame to decode

  200.     unsigned int frame_id;          ///< the frame ID / number of the current frame

  201.     unsigned int js_switch;         ///< if true, joint-stereo decoding is enforced

  202.     unsigned int num_blocks;        ///< number of blocks used in the current frame

  203.     unsigned int s_max;             ///< maximum Rice parameter allowed in entropy coding

  204.     uint8_t *bgmc_lut;              ///< pointer at lookup tables used for BGMC

  205.     int *bgmc_lut_status;           ///< pointer at lookup table status flags used for BGMC

  206.     int ltp_lag_length;             ///< number of bits used for ltp lag value

  207.     int *const_block;               ///< contains const_block flags for all channels

  208.     unsigned int *shift_lsbs;       ///< contains shift_lsbs flags for all channels

  209.     unsigned int *opt_order;        ///< contains opt_order flags for all channels

  210.     int *store_prev_samples;        ///< contains store_prev_samples flags for all channels

  211.     int *use_ltp;                   ///< contains use_ltp flags for all channels

  212.     int *ltp_lag;                   ///< contains ltp lag values for all channels

  213.     int **ltp_gain;                 ///< gain values for ltp 5-tap filter for a channel

  214.     int *ltp_gain_buffer;           ///< contains all gain values for ltp 5-tap filter

  215.     int32_t **quant_cof;            ///< quantized parcor coefficients for a channel

  216.     int32_t *quant_cof_buffer;      ///< contains all quantized parcor coefficients

  217.     int32_t **lpc_cof;              ///< coefficients of the direct form prediction filter for a channel

  218.     int32_t *lpc_cof_buffer;        ///< contains all coefficients of the direct form prediction filter

  219.     int32_t *lpc_cof_reversed_buffer; ///< temporary buffer to set up a reversed versio of lpc_cof_buffer

  220.     ALSChannelData **chan_data;     ///< channel data for multi-channel correlation

  221.     ALSChannelData *chan_data_buffer; ///< contains channel data for all channels

  222.     int *reverted_channels;         ///< stores a flag for each reverted channel

  223.     int32_t *prev_raw_samples;      ///< contains unshifted raw samples from the previous block

  224.     int32_t **raw_samples;          ///< decoded raw samples for each channel

  225.     int32_t *raw_buffer;            ///< contains all decoded raw samples including carryover samples

  226.     uint8_t *crc_buffer;            ///< buffer of byte order corrected samples used for CRC check

  227. } ALSDecContext;

  228. 

  229. 

  230. typedef struct ALSBlockData {

  231.     unsigned int block_length;      ///< number of samples within the block

  232.     unsigned int ra_block;          ///< if true, this is a random access block

  233.     int          *const_block;      ///< if true, this is a constant value block

  234.     int          js_blocks;         ///< true if this block contains a difference signal

  235.     unsigned int *shift_lsbs;       ///< shift of values for this block

  236.     unsigned int *opt_order;        ///< prediction order of this block

  237.     int          *store_prev_samples;///< if true, carryover samples have to be stored

  238.     int          *use_ltp;          ///< if true, long-term prediction is used

  239.     int          *ltp_lag;          ///< lag value for long-term prediction

  240.     int          *ltp_gain;         ///< gain values for ltp 5-tap filter

  241.     int32_t      *quant_cof;        ///< quantized parcor coefficients

  242.     int32_t      *lpc_cof;          ///< coefficients of the direct form prediction

  243.     int32_t      *raw_samples;      ///< decoded raw samples / residuals for this block

  244.     int32_t      *prev_raw_samples; ///< contains unshifted raw samples from the previous block

  245.     int32_t      *raw_other;        ///< decoded raw samples of the other channel of a channel pair

  246. } ALSBlockData;

  247. 

  248. 

  249. static av_cold void dprint_specific_config(ALSDecContext *ctx)

  250. {

  251. #ifdef DEBUG

  252.     AVCodecContext *avctx    = ctx->avctx;

  253.     ALSSpecificConfig *sconf = &ctx->sconf;

  254. 

  255.     ff_dlog(avctx, "resolution = %i\n",           sconf->resolution);

  256.     ff_dlog(avctx, "floating = %i\n",             sconf->floating);

  257.     ff_dlog(avctx, "frame_length = %i\n",         sconf->frame_length);

  258.     ff_dlog(avctx, "ra_distance = %i\n",          sconf->ra_distance);

  259.     ff_dlog(avctx, "ra_flag = %i\n",              sconf->ra_flag);

  260.     ff_dlog(avctx, "adapt_order = %i\n",          sconf->adapt_order);

  261.     ff_dlog(avctx, "coef_table = %i\n",           sconf->coef_table);

  262.     ff_dlog(avctx, "long_term_prediction = %i\n", sconf->long_term_prediction);

  263.     ff_dlog(avctx, "max_order = %i\n",            sconf->max_order);

  264.     ff_dlog(avctx, "block_switching = %i\n",      sconf->block_switching);

  265.     ff_dlog(avctx, "bgmc = %i\n",                 sconf->bgmc);

  266.     ff_dlog(avctx, "sb_part = %i\n",              sconf->sb_part);

  267.     ff_dlog(avctx, "joint_stereo = %i\n",         sconf->joint_stereo);

  268.     ff_dlog(avctx, "mc_coding = %i\n",            sconf->mc_coding);

  269.     ff_dlog(avctx, "chan_config = %i\n",          sconf->chan_config);

  270.     ff_dlog(avctx, "chan_sort = %i\n",            sconf->chan_sort);

  271.     ff_dlog(avctx, "RLSLMS = %i\n",               sconf->rlslms);

  272.     ff_dlog(avctx, "chan_config_info = %i\n",     sconf->chan_config_info);

  273. #endif

  274. }

  275. 

  276. 

  277. /** Read an ALSSpecificConfig from a buffer into the output struct.

  278.  */

  279. static av_cold int read_specific_config(ALSDecContext *ctx)

  280. {

  281.     GetBitContext gb;

  282.     uint64_t ht_size;

  283.     int i, config_offset;

  284.     MPEG4AudioConfig m4ac;

  285.     ALSSpecificConfig *sconf = &ctx->sconf;

  286.     AVCodecContext *avctx    = ctx->avctx;

  287.     uint32_t als_id, header_size, trailer_size;

  288. 

  289.     init_get_bits(&gb, avctx->extradata, avctx->extradata_size * 8);

  290. 

  291.     config_offset = avpriv_mpeg4audio_get_config(&m4ac, avctx->extradata,

  292.                                                  avctx->extradata_size * 8, 1);

  293. 

  294.     if (config_offset < 0)

  295.         return AVERROR_INVALIDDATA;

  296. 

  297.     skip_bits_long(&gb, config_offset);

  298. 

  299.     if (get_bits_left(&gb) < (30 << 3))

  300.         return AVERROR_INVALIDDATA;

  301. 

  302.     // read the fixed items

  303.     als_id                      = get_bits_long(&gb, 32);

  304.     avctx->sample_rate          = m4ac.sample_rate;

  305.     skip_bits_long(&gb, 32); // sample rate already known

  306.     sconf->samples              = get_bits_long(&gb, 32);

  307.     avctx->channels             = m4ac.channels;

  308.     skip_bits(&gb, 16);      // number of channels already known

  309.     skip_bits(&gb, 3);       // skip file_type

  310.     sconf->resolution           = get_bits(&gb, 3);

  311.     sconf->floating             = get_bits1(&gb);

  312.     sconf->msb_first            = get_bits1(&gb);

  313.     sconf->frame_length         = get_bits(&gb, 16) + 1;

  314.     sconf->ra_distance          = get_bits(&gb, 8);

  315.     sconf->ra_flag              = get_bits(&gb, 2);

  316.     sconf->adapt_order          = get_bits1(&gb);

  317.     sconf->coef_table           = get_bits(&gb, 2);

  318.     sconf->long_term_prediction = get_bits1(&gb);

  319.     sconf->max_order            = get_bits(&gb, 10);

  320.     sconf->block_switching      = get_bits(&gb, 2);

  321.     sconf->bgmc                 = get_bits1(&gb);

  322.     sconf->sb_part              = get_bits1(&gb);

  323.     sconf->joint_stereo         = get_bits1(&gb);

  324.     sconf->mc_coding            = get_bits1(&gb);

  325.     sconf->chan_config          = get_bits1(&gb);

  326.     sconf->chan_sort            = get_bits1(&gb);

  327.     sconf->crc_enabled          = get_bits1(&gb);

  328.     sconf->rlslms               = get_bits1(&gb);

  329.     skip_bits(&gb, 5);       // skip 5 reserved bits

  330.     skip_bits1(&gb);         // skip aux_data_enabled

  331. 

  332. 

  333.     // check for ALSSpecificConfig struct

  334.     if (als_id != MKBETAG('A','L','S','\0'))

  335.         return AVERROR_INVALIDDATA;

  336. 

  337.     ctx->cur_frame_length = sconf->frame_length;

  338. 

  339.     // read channel config

  340.     if (sconf->chan_config)

  341.         sconf->chan_config_info = get_bits(&gb, 16);

  342.     // TODO: use this to set avctx->channel_layout

  343. 

  344. 

  345.     // read channel sorting

  346.     if (sconf->chan_sort && avctx->channels > 1) {

  347.         int chan_pos_bits = av_ceil_log2(avctx->channels);

  348.         int bits_needed  = avctx->channels * chan_pos_bits + 7;

  349.         if (get_bits_left(&gb) < bits_needed)

  350.             return AVERROR_INVALIDDATA;

  351. 

  352.         if (!(sconf->chan_pos = av_malloc(avctx->channels * sizeof(*sconf->chan_pos))))

  353.             return AVERROR(ENOMEM);

  354. 

  355.         for (i = 0; i < avctx->channels; i++)

  356.             sconf->chan_pos[i] = get_bits(&gb, chan_pos_bits);

  357. 

  358.         align_get_bits(&gb);

  359.         // TODO: use this to actually do channel sorting

  360.     } else {

  361.         sconf->chan_sort = 0;

  362.     }

  363. 

  364. 

  365.     // read fixed header and trailer sizes,

  366.     // if size = 0xFFFFFFFF then there is no data field!

  367.     if (get_bits_left(&gb) < 64)

  368.         return AVERROR_INVALIDDATA;

  369. 

  370.     header_size  = get_bits_long(&gb, 32);

  371.     trailer_size = get_bits_long(&gb, 32);

  372.     if (header_size  == 0xFFFFFFFF)

  373.         header_size  = 0;

  374.     if (trailer_size == 0xFFFFFFFF)

  375.         trailer_size = 0;

  376. 

  377.     ht_size = ((int64_t)(header_size) + (int64_t)(trailer_size)) << 3;

  378. 

  379. 

  380.     // skip the header and trailer data

  381.     if (get_bits_left(&gb) < ht_size)

  382.         return AVERROR_INVALIDDATA;

  383. 

  384.     if (ht_size > INT32_MAX)

  385.         return AVERROR_PATCHWELCOME;

  386. 

  387.     skip_bits_long(&gb, ht_size);

  388. 

  389. 

  390.     // initialize CRC calculation

  391.     if (sconf->crc_enabled) {

  392.         if (get_bits_left(&gb) < 32)

  393.             return AVERROR_INVALIDDATA;

  394. 

  395.         if (avctx->err_recognition & AV_EF_CRCCHECK) {

  396.             ctx->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);

  397.             ctx->crc       = 0xFFFFFFFF;

  398.             ctx->crc_org   = ~get_bits_long(&gb, 32);

  399.         } else

  400.             skip_bits_long(&gb, 32);

  401.     }

  402. 

  403. 

  404.     // no need to read the rest of ALSSpecificConfig (ra_unit_size & aux data)

  405. 

  406.     dprint_specific_config(ctx);

  407. 

  408.     return 0;

  409. }

  410. 

  411. 

  412. /** Check the ALSSpecificConfig for unsupported features.

  413.  */

  414. static int check_specific_config(ALSDecContext *ctx)

  415. {

  416.     ALSSpecificConfig *sconf = &ctx->sconf;

  417.     int error = 0;

  418. 

  419.     // report unsupported feature and set error value

  420.     #define MISSING_ERR(cond, str, errval)              \

  421.     {                                                   \

  422.         if (cond) {                                     \

  423.             avpriv_report_missing_feature(ctx->avctx,   \

  424.                                           str);         \

  425.             error = errval;                             \

  426.         }                                               \

  427.     }

  428. 

  429.     MISSING_ERR(sconf->floating,  "Floating point decoding",     AVERROR_PATCHWELCOME);

  430.     MISSING_ERR(sconf->rlslms,    "Adaptive RLS-LMS prediction", AVERROR_PATCHWELCOME);

  431.     MISSING_ERR(sconf->chan_sort, "Channel sorting",             0);

  432. 

  433.     return error;

  434. }

  435. 

  436. 

  437. /** Parse the bs_info field to extract the block partitioning used in

  438.  *  block switching mode, refer to ISO/IEC 14496-3, section 11.6.2.

  439.  */

  440. static void parse_bs_info(const uint32_t bs_info, unsigned int n,

  441.                           unsigned int div, unsigned int **div_blocks,

  442.                           unsigned int *num_blocks)

  443. {

  444.     if (n < 31 && ((bs_info << n) & 0x40000000)) {

  445.         // if the level is valid and the investigated bit n is set

  446.         // then recursively check both children at bits (2n+1) and (2n+2)

  447.         n   *= 2;

  448.         div += 1;

  449.         parse_bs_info(bs_info, n + 1, div, div_blocks, num_blocks);

  450.         parse_bs_info(bs_info, n + 2, div, div_blocks, num_blocks);

  451.     } else {

  452.         // else the bit is not set or the last level has been reached

  453.         // (bit implicitly not set)

  454.         **div_blocks = div;

  455.         (*div_blocks)++;

  456.         (*num_blocks)++;

  457.     }

  458. }

  459. 

  460. 

  461. /** Read and decode a Rice codeword.

  462.  */

  463. static int32_t decode_rice(GetBitContext *gb, unsigned int k)

  464. {

  465.     int max = get_bits_left(gb) - k;

  466.     int q   = get_unary(gb, 0, max);

  467.     int r   = k ? get_bits1(gb) : !(q & 1);

  468. 

  469.     if (k > 1) {

  470.         q <<= (k - 1);

  471.         q  += get_bits_long(gb, k - 1);

  472.     } else if (!k) {

  473.         q >>= 1;

  474.     }

  475.     return r ? q : ~q;

  476. }

  477. 

  478. 

  479. /** Convert PARCOR coefficient k to direct filter coefficient.

  480.  */

  481. static void parcor_to_lpc(unsigned int k, const int32_t *par, int32_t *cof)

  482. {

  483.     int i, j;

  484. 

  485.     for (i = 0, j = k - 1; i < j; i++, j--) {

  486.         int tmp1 = ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);

  487.         cof[j]  += ((MUL64(par[k], cof[i]) + (1 << 19)) >> 20);

  488.         cof[i]  += tmp1;

  489.     }

  490.     if (i == j)

  491.         cof[i] += ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);

  492. 

  493.     cof[k] = par[k];

  494. }

  495. 

  496. 

  497. /** Read block switching field if necessary and set actual block sizes.

  498.  *  Also assure that the block sizes of the last frame correspond to the

  499.  *  actual number of samples.

  500.  */

  501. static void get_block_sizes(ALSDecContext *ctx, unsigned int *div_blocks,

  502.                             uint32_t *bs_info)

  503. {

  504.     ALSSpecificConfig *sconf     = &ctx->sconf;

  505.     GetBitContext *gb            = &ctx->gb;

  506.     unsigned int *ptr_div_blocks = div_blocks;

  507.     unsigned int b;

  508. 

  509.     if (sconf->block_switching) {

  510.         unsigned int bs_info_len = 1 << (sconf->block_switching + 2);

  511.         *bs_info = get_bits_long(gb, bs_info_len);

  512.         *bs_info <<= (32 - bs_info_len);

  513.     }

  514. 

  515.     ctx->num_blocks = 0;

  516.     parse_bs_info(*bs_info, 0, 0, &ptr_div_blocks, &ctx->num_blocks);

  517. 

  518.     // The last frame may have an overdetermined block structure given in

  519.     // the bitstream. In that case the defined block structure would need

  520.     // more samples than available to be consistent.

  521.     // The block structure is actually used but the block sizes are adapted

  522.     // to fit the actual number of available samples.

  523.     // Example: 5 samples, 2nd level block sizes: 2 2 2 2.

  524.     // This results in the actual block sizes:    2 2 1 0.

  525.     // This is not specified in 14496-3 but actually done by the reference

  526.     // codec RM22 revision 2.

  527.     // This appears to happen in case of an odd number of samples in the last

  528.     // frame which is actually not allowed by the block length switching part

  529.     // of 14496-3.

  530.     // The ALS conformance files feature an odd number of samples in the last

  531.     // frame.

  532. 

  533.     for (b = 0; b < ctx->num_blocks; b++)

  534.         div_blocks[b] = ctx->sconf.frame_length >> div_blocks[b];

  535. 

  536.     if (ctx->cur_frame_length != ctx->sconf.frame_length) {

  537.         unsigned int remaining = ctx->cur_frame_length;

  538. 

  539.         for (b = 0; b < ctx->num_blocks; b++) {

  540.             if (remaining <= div_blocks[b]) {

  541.                 div_blocks[b] = remaining;

  542.                 ctx->num_blocks = b + 1;

  543.                 break;

  544.             }

  545. 

  546.             remaining -= div_blocks[b];

  547.         }

  548.     }

  549. }

  550. 

  551. 

  552. /** Read the block data for a constant block

  553.  */

  554. static void read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)

  555. {

  556.     ALSSpecificConfig *sconf = &ctx->sconf;

  557.     AVCodecContext *avctx    = ctx->avctx;

  558.     GetBitContext *gb        = &ctx->gb;

  559. 

  560.     *bd->raw_samples = 0;

  561.     *bd->const_block = get_bits1(gb);    // 1 = constant value, 0 = zero block (silence)

  562.     bd->js_blocks    = get_bits1(gb);

  563. 

  564.     // skip 5 reserved bits

  565.     skip_bits(gb, 5);

  566. 

  567.     if (*bd->const_block) {

  568.         unsigned int const_val_bits = sconf->floating ? 24 : avctx->bits_per_raw_sample;

  569.         *bd->raw_samples = get_sbits_long(gb, const_val_bits);

  570.     }

  571. 

  572.     // ensure constant block decoding by reusing this field

  573.     *bd->const_block = 1;

  574. }

  575. 

  576. 

  577. /** Decode the block data for a constant block

  578.  */

  579. static void decode_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)

  580. {

  581.     int      smp = bd->block_length - 1;

  582.     int32_t  val = *bd->raw_samples;

  583.     int32_t *dst = bd->raw_samples + 1;

  584. 

  585.     // write raw samples into buffer

  586.     for (; smp; smp--)

  587.         *dst++ = val;

  588. }

  589. 

  590. 

  591. /** Read the block data for a non-constant block

  592.  */

  593. static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)

  594. {

  595.     ALSSpecificConfig *sconf = &ctx->sconf;

  596.     AVCodecContext *avctx    = ctx->avctx;

  597.     GetBitContext *gb        = &ctx->gb;

  598.     unsigned int k;

  599.     unsigned int s[8];

  600.     unsigned int sx[8];

  601.     unsigned int sub_blocks, log2_sub_blocks, sb_length;

  602.     unsigned int start      = 0;

  603.     unsigned int opt_order;

  604.     int          sb;

  605.     int32_t      *quant_cof = bd->quant_cof;

  606.     int32_t      *current_res;

  607. 

  608. 

  609.     // ensure variable block decoding by reusing this field

  610.     *bd->const_block = 0;

  611. 

  612.     *bd->opt_order  = 1;

  613.     bd->js_blocks   = get_bits1(gb);

  614. 

  615.     opt_order       = *bd->opt_order;

  616. 

  617.     // determine the number of subblocks for entropy decoding

  618.     if (!sconf->bgmc && !sconf->sb_part) {

  619.         log2_sub_blocks = 0;

  620.     } else {

  621.         if (sconf->bgmc && sconf->sb_part)

  622.             log2_sub_blocks = get_bits(gb, 2);

  623.         else

  624.             log2_sub_blocks = 2 * get_bits1(gb);

  625.     }

  626. 

  627.     sub_blocks = 1 << log2_sub_blocks;

  628. 

  629.     // do not continue in case of a damaged stream since

  630.     // block_length must be evenly divisible by sub_blocks

  631.     if (bd->block_length & (sub_blocks - 1)) {

  632.         av_log(avctx, AV_LOG_WARNING,

  633.                "Block length is not evenly divisible by the number of subblocks.\n");

  634.         return AVERROR_INVALIDDATA;

  635.     }

  636. 

  637.     sb_length = bd->block_length >> log2_sub_blocks;

  638. 

  639.     if (sconf->bgmc) {

  640.         s[0] = get_bits(gb, 8 + (sconf->resolution > 1));

  641.         for (k = 1; k < sub_blocks; k++)

  642.             s[k] = s[k - 1] + decode_rice(gb, 2);

  643. 

  644.         for (k = 0; k < sub_blocks; k++) {

  645.             sx[k]   = s[k] & 0x0F;

  646.             s [k] >>= 4;

  647.         }

  648.     } else {

  649.         s[0] = get_bits(gb, 4 + (sconf->resolution > 1));

  650.         for (k = 1; k < sub_blocks; k++)

  651.             s[k] = s[k - 1] + decode_rice(gb, 0);

  652.     }

  653.     for (k = 1; k < sub_blocks; k++)

  654.         if (s[k] > 32) {

  655.             av_log(avctx, AV_LOG_ERROR, "k invalid for rice code.\n");

  656.             return AVERROR_INVALIDDATA;

  657.         }

  658. 

  659.     if (get_bits1(gb))

  660.         *bd->shift_lsbs = get_bits(gb, 4) + 1;

  661. 

  662.     *bd->store_prev_samples = (bd->js_blocks && bd->raw_other) || *bd->shift_lsbs;

  663. 

  664. 

  665.     if (!sconf->rlslms) {

  666.         if (sconf->adapt_order && sconf->max_order) {

  667.             int opt_order_length = av_ceil_log2(av_clip((bd->block_length >> 3) - 1,

  668.                                                 2, sconf->max_order + 1));

  669.             *bd->opt_order       = get_bits(gb, opt_order_length);

  670.             if (*bd->opt_order > sconf->max_order) {

  671.                 *bd->opt_order = sconf->max_order;

  672.                 av_log(avctx, AV_LOG_ERROR, "Predictor order too large!\n");

  673.                 return AVERROR_INVALIDDATA;

  674.             }

  675.         } else {

  676.             *bd->opt_order = sconf->max_order;

  677.         }

  678. 

  679.         opt_order = *bd->opt_order;

  680. 

  681.         if (opt_order) {

  682.             int add_base;

  683. 

  684.             if (sconf->coef_table == 3) {

  685.                 add_base = 0x7F;

  686. 

  687.                 // read coefficient 0

  688.                 quant_cof[0] = 32 * parcor_scaled_values[get_bits(gb, 7)];

  689. 

  690.                 // read coefficient 1

  691.                 if (opt_order > 1)

  692.                     quant_cof[1] = -32 * parcor_scaled_values[get_bits(gb, 7)];

  693. 

  694.                 // read coefficients 2 to opt_order

  695.                 for (k = 2; k < opt_order; k++)

  696.                     quant_cof[k] = get_bits(gb, 7);

  697.             } else {

  698.                 int k_max;

  699.                 add_base = 1;

  700. 

  701.                 // read coefficient 0 to 19

  702.                 k_max = FFMIN(opt_order, 20);

  703.                 for (k = 0; k < k_max; k++) {

  704.                     int rice_param = parcor_rice_table[sconf->coef_table][k][1];

  705.                     int offset     = parcor_rice_table[sconf->coef_table][k][0];

  706.                     quant_cof[k] = decode_rice(gb, rice_param) + offset;

  707.                     if (quant_cof[k] < -64 || quant_cof[k] > 63) {

  708.                         av_log(avctx, AV_LOG_ERROR,

  709.                                "quant_cof %"PRIu32" is out of range\n",

  710.                                quant_cof[k]);

  711.                         return AVERROR_INVALIDDATA;

  712.                     }

  713.                 }

  714. 

  715.                 // read coefficients 20 to 126

  716.                 k_max = FFMIN(opt_order, 127);

  717.                 for (; k < k_max; k++)

  718.                     quant_cof[k] = decode_rice(gb, 2) + (k & 1);

  719. 

  720.                 // read coefficients 127 to opt_order

  721.                 for (; k < opt_order; k++)

  722.                     quant_cof[k] = decode_rice(gb, 1);

  723. 

  724.                 quant_cof[0] = 32 * parcor_scaled_values[quant_cof[0] + 64];

  725. 

  726.                 if (opt_order > 1)

  727.                     quant_cof[1] = -32 * parcor_scaled_values[quant_cof[1] + 64];

  728.             }

  729. 

  730.             for (k = 2; k < opt_order; k++)

  731.                 quant_cof[k] = (quant_cof[k] << 14) + (add_base << 13);

  732.         }

  733.     }

  734. 

  735.     // read LTP gain and lag values

  736.     if (sconf->long_term_prediction) {

  737.         *bd->use_ltp = get_bits1(gb);

  738. 

  739.         if (*bd->use_ltp) {

  740.             int r, c;

  741. 

  742.             bd->ltp_gain[0]   = decode_rice(gb, 1) << 3;

  743.             bd->ltp_gain[1]   = decode_rice(gb, 2) << 3;

  744. 

  745.             r                 = get_unary(gb, 0, 3);

  746.             c                 = get_bits(gb, 2);

  747.             bd->ltp_gain[2]   = ltp_gain_values[r][c];

  748. 

  749.             bd->ltp_gain[3]   = decode_rice(gb, 2) << 3;

  750.             bd->ltp_gain[4]   = decode_rice(gb, 1) << 3;

  751. 

  752.             *bd->ltp_lag      = get_bits(gb, ctx->ltp_lag_length);

  753.             *bd->ltp_lag     += FFMAX(4, opt_order + 1);

  754.         }

  755.     }

  756. 

  757.     // read first value and residuals in case of a random access block

  758.     if (bd->ra_block) {

  759.         if (opt_order)

  760.             bd->raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4);

  761.         if (opt_order > 1)

  762.             bd->raw_samples[1] = decode_rice(gb, FFMIN(s[0] + 3, ctx->s_max));

  763.         if (opt_order > 2)

  764.             bd->raw_samples[2] = decode_rice(gb, FFMIN(s[0] + 1, ctx->s_max));

  765. 

  766.         start = FFMIN(opt_order, 3);

  767.     }

  768. 

  769.     // read all residuals

  770.     if (sconf->bgmc) {

  771.         int          delta[8];

  772.         unsigned int k    [8];

  773.         unsigned int b = av_clip((av_ceil_log2(bd->block_length) - 3) >> 1, 0, 5);

  774. 

  775.         // read most significant bits

  776.         unsigned int high;

  777.         unsigned int low;

  778.         unsigned int value;

  779. 

  780.         ff_bgmc_decode_init(gb, &high, &low, &value);

  781. 

  782.         current_res = bd->raw_samples + start;

  783. 

  784.         for (sb = 0; sb < sub_blocks; sb++) {

  785.             unsigned int sb_len  = sb_length - (sb ? 0 : start);

  786. 

  787.             k    [sb] = s[sb] > b ? s[sb] - b : 0;

  788.             delta[sb] = 5 - s[sb] + k[sb];

  789. 

  790.             ff_bgmc_decode(gb, sb_len, current_res,

  791.                         delta[sb], sx[sb], &high, &low, &value, ctx->bgmc_lut, ctx->bgmc_lut_status);

  792. 

  793.             current_res += sb_len;

  794.         }

  795. 

  796.         ff_bgmc_decode_end(gb);

  797. 

  798. 

  799.         // read least significant bits and tails

  800.         current_res = bd->raw_samples + start;

  801. 

  802.         for (sb = 0; sb < sub_blocks; sb++, start = 0) {

  803.             unsigned int cur_tail_code = tail_code[sx[sb]][delta[sb]];

  804.             unsigned int cur_k         = k[sb];

  805.             unsigned int cur_s         = s[sb];

  806. 

  807.             for (; start < sb_length; start++) {

  808.                 int32_t res = *current_res;

  809. 

  810.                 if (res == cur_tail_code) {

  811.                     unsigned int max_msb =   (2 + (sx[sb] > 2) + (sx[sb] > 10))

  812.                                           << (5 - delta[sb]);

  813. 

  814.                     res = decode_rice(gb, cur_s);

  815. 

  816.                     if (res >= 0) {

  817.                         res += (max_msb    ) << cur_k;

  818.                     } else {

  819.                         res -= (max_msb - 1) << cur_k;

  820.                     }

  821.                 } else {

  822.                     if (res > cur_tail_code)

  823.                         res--;

  824. 

  825.                     if (res & 1)

  826.                         res = -res;

  827. 

  828.                     res >>= 1;

  829. 

  830.                     if (cur_k) {

  831.                         res <<= cur_k;

  832.                         res  |= get_bits_long(gb, cur_k);

  833.                     }

  834.                 }

  835. 

  836.                 *current_res++ = res;

  837.             }

  838.         }

  839.     } else {

  840.         current_res = bd->raw_samples + start;

  841. 

  842.         for (sb = 0; sb < sub_blocks; sb++, start = 0)

  843.             for (; start < sb_length; start++)

  844.                 *current_res++ = decode_rice(gb, s[sb]);

  845.      }

  846. 

  847.     if (!sconf->mc_coding || ctx->js_switch)

  848.         align_get_bits(gb);

  849. 

  850.     return 0;

  851. }

  852. 

  853. 

  854. /** Decode the block data for a non-constant block

  855.  */

  856. static int decode_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)

  857. {

  858.     ALSSpecificConfig *sconf = &ctx->sconf;

  859.     unsigned int block_length = bd->block_length;

  860.     unsigned int smp = 0;

  861.     unsigned int k;

  862.     int opt_order             = *bd->opt_order;

  863.     int sb;

  864.     int64_t y;

  865.     int32_t *quant_cof        = bd->quant_cof;

  866.     int32_t *lpc_cof          = bd->lpc_cof;

  867.     int32_t *raw_samples      = bd->raw_samples;

  868.     int32_t *raw_samples_end  = bd->raw_samples + bd->block_length;

  869.     int32_t *lpc_cof_reversed = ctx->lpc_cof_reversed_buffer;

  870. 

  871.     // reverse long-term prediction

  872.     if (*bd->use_ltp) {

  873.         int ltp_smp;

  874. 

  875.         for (ltp_smp = FFMAX(*bd->ltp_lag - 2, 0); ltp_smp < block_length; ltp_smp++) {

  876.             int center = ltp_smp - *bd->ltp_lag;

  877.             int begin  = FFMAX(0, center - 2);

  878.             int end    = center + 3;

  879.             int tab    = 5 - (end - begin);

  880.             int base;

  881. 

  882.             y = 1 << 6;

  883. 

  884.             for (base = begin; base < end; base++, tab++)

  885.                 y += MUL64(bd->ltp_gain[tab], raw_samples[base]);

  886. 

  887.             raw_samples[ltp_smp] += y >> 7;

  888.         }

  889.     }

  890. 

  891.     // reconstruct all samples from residuals

  892.     if (bd->ra_block) {

  893.         for (smp = 0; smp < opt_order; smp++) {

  894.             y = 1 << 19;

  895. 

  896.             for (sb = 0; sb < smp; sb++)

  897.                 y += MUL64(lpc_cof[sb], raw_samples[-(sb + 1)]);

  898. 

  899.             *raw_samples++ -= y >> 20;

  900.             parcor_to_lpc(smp, quant_cof, lpc_cof);

  901.         }

  902.     } else {

  903.         for (k = 0; k < opt_order; k++)

  904.             parcor_to_lpc(k, quant_cof, lpc_cof);

  905. 

  906.         // store previous samples in case that they have to be altered

  907.         if (*bd->store_prev_samples)

  908.             memcpy(bd->prev_raw_samples, raw_samples - sconf->max_order,

  909.                    sizeof(*bd->prev_raw_samples) * sconf->max_order);

  910. 

  911.         // reconstruct difference signal for prediction (joint-stereo)

  912.         if (bd->js_blocks && bd->raw_other) {

  913.             int32_t *left, *right;

  914. 

  915.             if (bd->raw_other > raw_samples) {  // D = R - L

  916.                 left  = raw_samples;

  917.                 right = bd->raw_other;

  918.             } else {                                // D = R - L

  919.                 left  = bd->raw_other;

  920.                 right = raw_samples;

  921.             }

  922. 

  923.             for (sb = -1; sb >= -sconf->max_order; sb--)

  924.                 raw_samples[sb] = right[sb] - left[sb];

  925.         }

  926. 

  927.         // reconstruct shifted signal

  928.         if (*bd->shift_lsbs)

  929.             for (sb = -1; sb >= -sconf->max_order; sb--)

  930.                 raw_samples[sb] >>= *bd->shift_lsbs;

  931.     }

  932. 

  933.     // reverse linear prediction coefficients for efficiency

  934.     lpc_cof = lpc_cof + opt_order;

  935. 

  936.     for (sb = 0; sb < opt_order; sb++)

  937.         lpc_cof_reversed[sb] = lpc_cof[-(sb + 1)];

  938. 

  939.     // reconstruct raw samples

  940.     raw_samples = bd->raw_samples + smp;

  941.     lpc_cof     = lpc_cof_reversed + opt_order;

  942. 

  943.     for (; raw_samples < raw_samples_end; raw_samples++) {

  944.         y = 1 << 19;

  945. 

  946.         for (sb = -opt_order; sb < 0; sb++)

  947.             y += MUL64(lpc_cof[sb], raw_samples[sb]);

  948. 

  949.         *raw_samples -= y >> 20;

  950.     }

  951. 

  952.     raw_samples = bd->raw_samples;

  953. 

  954.     // restore previous samples in case that they have been altered

  955.     if (*bd->store_prev_samples)

  956.         memcpy(raw_samples - sconf->max_order, bd->prev_raw_samples,

  957.                sizeof(*raw_samples) * sconf->max_order);

  958. 

  959.     return 0;

  960. }

  961. 

  962. 

  963. /** Read the block data.

  964.  */

  965. static int read_block(ALSDecContext *ctx, ALSBlockData *bd)

  966. {

  967.     int ret = 0;

  968.     GetBitContext *gb        = &ctx->gb;

  969. 

  970.     *bd->shift_lsbs = 0;

  971.     // read block type flag and read the samples accordingly

  972.     if (get_bits1(gb)) {

  973.         ret = read_var_block_data(ctx, bd);

  974.     } else {

  975.         read_const_block_data(ctx, bd);

  976.     }

  977. 

  978.     return ret;

  979. }

  980. 

  981. 

  982. /** Decode the block data.

  983.  */

  984. static int decode_block(ALSDecContext *ctx, ALSBlockData *bd)

  985. {

  986.     unsigned int smp;

  987.     int ret = 0;

  988. 

  989.     // read block type flag and read the samples accordingly

  990.     if (*bd->const_block)

  991.         decode_const_block_data(ctx, bd);

  992.     else

  993.         ret = decode_var_block_data(ctx, bd); // always return 0

  994. 

  995.     if (ret < 0)

  996.         return ret;

  997. 

  998.     // TODO: read RLSLMS extension data

  999. 

  1000.     if (*bd->shift_lsbs)

  1001.         for (smp = 0; smp < bd->block_length; smp++)

  1002.             bd->raw_samples[smp] <<= *bd->shift_lsbs;

  1003. 

  1004.     return 0;

  1005. }

  1006. 

  1007. 

  1008. /** Read and decode block data successively.

  1009.  */

  1010. static int read_decode_block(ALSDecContext *ctx, ALSBlockData *bd)

  1011. {

  1012.     int ret;

  1013. 

  1014.     if ((ret = read_block(ctx, bd)) < 0)

  1015.         return ret;

  1016. 

  1017.     return decode_block(ctx, bd);

  1018. }

  1019. 

  1020. 

  1021. /** Compute the number of samples left to decode for the current frame and

  1022.  *  sets these samples to zero.

  1023.  */

  1024. static void zero_remaining(unsigned int b, unsigned int b_max,

  1025.                            const unsigned int *div_blocks, int32_t *buf)

  1026. {

  1027.     unsigned int count = 0;

  1028. 

  1029.     for (; b < b_max; b++)

  1030.         count += div_blocks[b];

  1031. 

  1032.     if (count)

  1033.         memset(buf, 0, sizeof(*buf) * count);

  1034. }

  1035. 

  1036. 

  1037. /** Decode blocks independently.

  1038.  */

  1039. static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,

  1040.                              unsigned int c, const unsigned int *div_blocks,

  1041.                              unsigned int *js_blocks)

  1042. {

  1043.     int ret;

  1044.     unsigned int b;

  1045.     ALSBlockData bd = { 0 };

  1046. 

  1047.     bd.ra_block         = ra_frame;

  1048.     bd.const_block      = ctx->const_block;

  1049.     bd.shift_lsbs       = ctx->shift_lsbs;

  1050.     bd.opt_order        = ctx->opt_order;

  1051.     bd.store_prev_samples = ctx->store_prev_samples;

  1052.     bd.use_ltp          = ctx->use_ltp;

  1053.     bd.ltp_lag          = ctx->ltp_lag;

  1054.     bd.ltp_gain         = ctx->ltp_gain[0];

  1055.     bd.quant_cof        = ctx->quant_cof[0];

  1056.     bd.lpc_cof          = ctx->lpc_cof[0];

  1057.     bd.prev_raw_samples = ctx->prev_raw_samples;

  1058.     bd.raw_samples      = ctx->raw_samples[c];

  1059. 

  1060. 

  1061.     for (b = 0; b < ctx->num_blocks; b++) {

  1062.         bd.block_length     = div_blocks[b];

  1063. 

  1064.         if ((ret = read_decode_block(ctx, &bd)) < 0) {

  1065.             // damaged block, write zero for the rest of the frame

  1066.             zero_remaining(b, ctx->num_blocks, div_blocks, bd.raw_samples);

  1067.             return ret;

  1068.         }

  1069.         bd.raw_samples += div_blocks[b];

  1070.         bd.ra_block     = 0;

  1071.     }

  1072. 

  1073.     return 0;

  1074. }

  1075. 

  1076. 

  1077. /** Decode blocks dependently.

  1078.  */

  1079. static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,

  1080.                          unsigned int c, const unsigned int *div_blocks,

  1081.                          unsigned int *js_blocks)

  1082. {

  1083.     ALSSpecificConfig *sconf = &ctx->sconf;

  1084.     unsigned int offset = 0;

  1085.     unsigned int b;

  1086.     int ret;

  1087.     ALSBlockData bd[2] = { { 0 } };

  1088. 

  1089.     bd[0].ra_block         = ra_frame;

  1090.     bd[0].const_block      = ctx->const_block;

  1091.     bd[0].shift_lsbs       = ctx->shift_lsbs;

  1092.     bd[0].opt_order        = ctx->opt_order;

  1093.     bd[0].store_prev_samples = ctx->store_prev_samples;

  1094.     bd[0].use_ltp          = ctx->use_ltp;

  1095.     bd[0].ltp_lag          = ctx->ltp_lag;

  1096.     bd[0].ltp_gain         = ctx->ltp_gain[0];

  1097.     bd[0].quant_cof        = ctx->quant_cof[0];

  1098.     bd[0].lpc_cof          = ctx->lpc_cof[0];

  1099.     bd[0].prev_raw_samples = ctx->prev_raw_samples;

  1100.     bd[0].js_blocks        = *js_blocks;

  1101. 

  1102.     bd[1].ra_block         = ra_frame;

  1103.     bd[1].const_block      = ctx->const_block;

  1104.     bd[1].shift_lsbs       = ctx->shift_lsbs;

  1105.     bd[1].opt_order        = ctx->opt_order;

  1106.     bd[1].store_prev_samples = ctx->store_prev_samples;

  1107.     bd[1].use_ltp          = ctx->use_ltp;

  1108.     bd[1].ltp_lag          = ctx->ltp_lag;

  1109.     bd[1].ltp_gain         = ctx->ltp_gain[0];

  1110.     bd[1].quant_cof        = ctx->quant_cof[0];

  1111.     bd[1].lpc_cof          = ctx->lpc_cof[0];

  1112.     bd[1].prev_raw_samples = ctx->prev_raw_samples;

  1113.     bd[1].js_blocks        = *(js_blocks + 1);

  1114. 

  1115.     // decode all blocks

  1116.     for (b = 0; b < ctx->num_blocks; b++) {

  1117.         unsigned int s;

  1118. 

  1119.         bd[0].block_length = div_blocks[b];

  1120.         bd[1].block_length = div_blocks[b];

  1121. 

  1122.         bd[0].raw_samples  = ctx->raw_samples[c    ] + offset;

  1123.         bd[1].raw_samples  = ctx->raw_samples[c + 1] + offset;

  1124. 

  1125.         bd[0].raw_other    = bd[1].raw_samples;

  1126.         bd[1].raw_other    = bd[0].raw_samples;

  1127. 

  1128.         if ((ret = read_decode_block(ctx, &bd[0])) < 0 ||

  1129.             (ret = read_decode_block(ctx, &bd[1])) < 0)

  1130.             goto fail;

  1131. 

  1132.         // reconstruct joint-stereo blocks

  1133.         if (bd[0].js_blocks) {

  1134.             if (bd[1].js_blocks)

  1135.                 av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair!\n");

  1136. 

  1137.             for (s = 0; s < div_blocks[b]; s++)

  1138.                 bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];

  1139.         } else if (bd[1].js_blocks) {

  1140.             for (s = 0; s < div_blocks[b]; s++)

  1141.                 bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];

  1142.         }

  1143. 

  1144.         offset  += div_blocks[b];

  1145.         bd[0].ra_block = 0;

  1146.         bd[1].ra_block = 0;

  1147.     }

  1148. 

  1149.     // store carryover raw samples,

  1150.     // the others channel raw samples are stored by the calling function.

  1151.     memmove(ctx->raw_samples[c] - sconf->max_order,

  1152.             ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1153.             sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1154. 

  1155.     return 0;

  1156. fail:

  1157.     // damaged block, write zero for the rest of the frame

  1158.     zero_remaining(b, ctx->num_blocks, div_blocks, bd[0].raw_samples);

  1159.     zero_remaining(b, ctx->num_blocks, div_blocks, bd[1].raw_samples);

  1160.     return ret;

  1161. }

  1162. 

  1163. static inline int als_weighting(GetBitContext *gb, int k, int off)

  1164. {

  1165.     int idx = av_clip(decode_rice(gb, k) + off,

  1166.                       0, FF_ARRAY_ELEMS(mcc_weightings) - 1);

  1167.     return mcc_weightings[idx];

  1168. }

  1169. 

  1170. /** Read the channel data.

  1171.   */

  1172. static int read_channel_data(ALSDecContext *ctx, ALSChannelData *cd, int c)

  1173. {

  1174.     GetBitContext *gb       = &ctx->gb;

  1175.     ALSChannelData *current = cd;

  1176.     unsigned int channels   = ctx->avctx->channels;

  1177.     int entries             = 0;

  1178. 

  1179.     while (entries < channels && !(current->stop_flag = get_bits1(gb))) {

  1180.         current->master_channel = get_bits_long(gb, av_ceil_log2(channels));

  1181. 

  1182.         if (current->master_channel >= channels) {

  1183.             av_log(ctx->avctx, AV_LOG_ERROR, "Invalid master channel!\n");

  1184.             return AVERROR_INVALIDDATA;

  1185.         }

  1186. 

  1187.         if (current->master_channel != c) {

  1188.             current->time_diff_flag = get_bits1(gb);

  1189.             current->weighting[0]   = als_weighting(gb, 1, 16);

  1190.             current->weighting[1]   = als_weighting(gb, 2, 14);

  1191.             current->weighting[2]   = als_weighting(gb, 1, 16);

  1192. 

  1193.             if (current->time_diff_flag) {

  1194.                 current->weighting[3] = als_weighting(gb, 1, 16);

  1195.                 current->weighting[4] = als_weighting(gb, 1, 16);

  1196.                 current->weighting[5] = als_weighting(gb, 1, 16);

  1197. 

  1198.                 current->time_diff_sign  = get_bits1(gb);

  1199.                 current->time_diff_index = get_bits(gb, ctx->ltp_lag_length - 3) + 3;

  1200.             }

  1201.         }

  1202. 

  1203.         current++;

  1204.         entries++;

  1205.     }

  1206. 

  1207.     if (entries == channels) {

  1208.         av_log(ctx->avctx, AV_LOG_ERROR, "Damaged channel data!\n");

  1209.         return AVERROR_INVALIDDATA;

  1210.     }

  1211. 

  1212.     align_get_bits(gb);

  1213.     return 0;

  1214. }

  1215. 

  1216. 

  1217. /** Recursively reverts the inter-channel correlation for a block.

  1218.  */

  1219. static int revert_channel_correlation(ALSDecContext *ctx, ALSBlockData *bd,

  1220.                                        ALSChannelData **cd, int *reverted,

  1221.                                        unsigned int offset, int c)

  1222. {

  1223.     ALSChannelData *ch = cd[c];

  1224.     unsigned int   dep = 0;

  1225.     unsigned int channels = ctx->avctx->channels;

  1226.     unsigned int channel_size = ctx->sconf.frame_length + ctx->sconf.max_order;

  1227. 

  1228.     if (reverted[c])

  1229.         return 0;

  1230. 

  1231.     reverted[c] = 1;

  1232. 

  1233.     while (dep < channels && !ch[dep].stop_flag) {

  1234.         revert_channel_correlation(ctx, bd, cd, reverted, offset,

  1235.                                    ch[dep].master_channel);

  1236. 

  1237.         dep++;

  1238.     }

  1239. 

  1240.     if (dep == channels) {

  1241.         av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel correlation!\n");

  1242.         return AVERROR_INVALIDDATA;

  1243.     }

  1244. 

  1245.     bd->const_block = ctx->const_block + c;

  1246.     bd->shift_lsbs  = ctx->shift_lsbs + c;

  1247.     bd->opt_order   = ctx->opt_order + c;

  1248.     bd->store_prev_samples = ctx->store_prev_samples + c;

  1249.     bd->use_ltp     = ctx->use_ltp + c;

  1250.     bd->ltp_lag     = ctx->ltp_lag + c;

  1251.     bd->ltp_gain    = ctx->ltp_gain[c];

  1252.     bd->lpc_cof     = ctx->lpc_cof[c];

  1253.     bd->quant_cof   = ctx->quant_cof[c];

  1254.     bd->raw_samples = ctx->raw_samples[c] + offset;

  1255. 

  1256.     dep = 0;

  1257.     while (!ch[dep].stop_flag) {

  1258.         ptrdiff_t smp;

  1259.         ptrdiff_t begin = 1;

  1260.         ptrdiff_t end   = bd->block_length - 1;

  1261.         int64_t y;

  1262.         int32_t *master = ctx->raw_samples[ch[dep].master_channel] + offset;

  1263. 

  1264.         if (ch[dep].time_diff_flag) {

  1265.             int t = ch[dep].time_diff_index;

  1266. 

  1267.             if (ch[dep].time_diff_sign) {

  1268.                 t      = -t;

  1269.                 begin -= t;

  1270.             } else {

  1271.                 end   -= t;

  1272.             }

  1273. 

  1274.             if (FFMIN(begin - 1, begin - 1 + t) < ctx->raw_buffer - master ||

  1275.                 FFMAX(end   + 1,   end + 1 + t) > ctx->raw_buffer + channels * channel_size - master) {

  1276.                 av_log(ctx->avctx, AV_LOG_ERROR,

  1277.                        "sample pointer range [%p, %p] not contained in raw_buffer [%p, %p].\n",

  1278.                        master + FFMIN(begin - 1, begin - 1 + t), master + FFMAX(end + 1,   end + 1 + t),

  1279.                        ctx->raw_buffer, ctx->raw_buffer + channels * channel_size);

  1280.                 return AVERROR_INVALIDDATA;

  1281.             }

  1282. 

  1283.             for (smp = begin; smp < end; smp++) {

  1284.                 y  = (1 << 6) +

  1285.                      MUL64(ch[dep].weighting[0], master[smp - 1    ]) +

  1286.                      MUL64(ch[dep].weighting[1], master[smp        ]) +

  1287.                      MUL64(ch[dep].weighting[2], master[smp + 1    ]) +

  1288.                      MUL64(ch[dep].weighting[3], master[smp - 1 + t]) +

  1289.                      MUL64(ch[dep].weighting[4], master[smp     + t]) +

  1290.                      MUL64(ch[dep].weighting[5], master[smp + 1 + t]);

  1291. 

  1292.                 bd->raw_samples[smp] += y >> 7;

  1293.             }

  1294.         } else {

  1295. 

  1296.             if (begin - 1 < ctx->raw_buffer - master ||

  1297.                 end   + 1 > ctx->raw_buffer + channels * channel_size - master) {

  1298.                 av_log(ctx->avctx, AV_LOG_ERROR,

  1299.                        "sample pointer range [%p, %p] not contained in raw_buffer [%p, %p].\n",

  1300.                        master + begin - 1, master + end + 1,

  1301.                        ctx->raw_buffer, ctx->raw_buffer + channels * channel_size);

  1302.                 return AVERROR_INVALIDDATA;

  1303.             }

  1304. 

  1305.             for (smp = begin; smp < end; smp++) {

  1306.                 y  = (1 << 6) +

  1307.                      MUL64(ch[dep].weighting[0], master[smp - 1]) +

  1308.                      MUL64(ch[dep].weighting[1], master[smp    ]) +

  1309.                      MUL64(ch[dep].weighting[2], master[smp + 1]);

  1310. 

  1311.                 bd->raw_samples[smp] += y >> 7;

  1312.             }

  1313.         }

  1314. 

  1315.         dep++;

  1316.     }

  1317. 

  1318.     return 0;

  1319. }

  1320. 

  1321. 

  1322. /** Read the frame data.

  1323.  */

  1324. static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)

  1325. {

  1326.     ALSSpecificConfig *sconf = &ctx->sconf;

  1327.     AVCodecContext *avctx    = ctx->avctx;

  1328.     GetBitContext *gb = &ctx->gb;

  1329.     unsigned int div_blocks[32];                ///< block sizes.

  1330.     unsigned int c;

  1331.     unsigned int js_blocks[2];

  1332.     uint32_t bs_info = 0;

  1333.     int ret;

  1334. 

  1335.     // skip the size of the ra unit if present in the frame

  1336.     if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)

  1337.         skip_bits_long(gb, 32);

  1338. 

  1339.     if (sconf->mc_coding && sconf->joint_stereo) {

  1340.         ctx->js_switch = get_bits1(gb);

  1341.         align_get_bits(gb);

  1342.     }

  1343. 

  1344.     if (!sconf->mc_coding || ctx->js_switch) {

  1345.         int independent_bs = !sconf->joint_stereo;

  1346. 

  1347.         for (c = 0; c < avctx->channels; c++) {

  1348.             js_blocks[0] = 0;

  1349.             js_blocks[1] = 0;

  1350. 

  1351.             get_block_sizes(ctx, div_blocks, &bs_info);

  1352. 

  1353.             // if joint_stereo and block_switching is set, independent decoding

  1354.             // is signaled via the first bit of bs_info

  1355.             if (sconf->joint_stereo && sconf->block_switching)

  1356.                 if (bs_info >> 31)

  1357.                     independent_bs = 2;

  1358. 

  1359.             // if this is the last channel, it has to be decoded independently

  1360.             if (c == avctx->channels - 1)

  1361.                 independent_bs = 1;

  1362. 

  1363.             if (independent_bs) {

  1364.                 ret = decode_blocks_ind(ctx, ra_frame, c,

  1365.                                         div_blocks, js_blocks);

  1366.                 if (ret < 0)

  1367.                     return ret;

  1368.                 independent_bs--;

  1369.             } else {

  1370.                 ret = decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks);

  1371.                 if (ret < 0)

  1372.                     return ret;

  1373. 

  1374.                 c++;

  1375.             }

  1376. 

  1377.             // store carryover raw samples

  1378.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1379.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1380.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1381.         }

  1382.     } else { // multi-channel coding

  1383.         ALSBlockData   bd = { 0 };

  1384.         int            b, ret;

  1385.         int            *reverted_channels = ctx->reverted_channels;

  1386.         unsigned int   offset             = 0;

  1387. 

  1388.         for (c = 0; c < avctx->channels; c++)

  1389.             if (ctx->chan_data[c] < ctx->chan_data_buffer) {

  1390.                 av_log(ctx->avctx, AV_LOG_ERROR, "Invalid channel data!\n");

  1391.                 return AVERROR_INVALIDDATA;

  1392.             }

  1393. 

  1394.         memset(reverted_channels, 0, sizeof(*reverted_channels) * avctx->channels);

  1395. 

  1396.         bd.ra_block         = ra_frame;

  1397.         bd.prev_raw_samples = ctx->prev_raw_samples;

  1398. 

  1399.         get_block_sizes(ctx, div_blocks, &bs_info);

  1400. 

  1401.         for (b = 0; b < ctx->num_blocks; b++) {

  1402.             bd.block_length = div_blocks[b];

  1403.             if (bd.block_length <= 0) {

  1404.                 av_log(ctx->avctx, AV_LOG_WARNING,

  1405.                        "Invalid block length %u in channel data!\n",

  1406.                        bd.block_length);

  1407.                 continue;

  1408.             }

  1409. 

  1410.             for (c = 0; c < avctx->channels; c++) {

  1411.                 bd.const_block = ctx->const_block + c;

  1412.                 bd.shift_lsbs  = ctx->shift_lsbs + c;

  1413.                 bd.opt_order   = ctx->opt_order + c;

  1414.                 bd.store_prev_samples = ctx->store_prev_samples + c;

  1415.                 bd.use_ltp     = ctx->use_ltp + c;

  1416.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1417.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1418.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1419.                 bd.quant_cof   = ctx->quant_cof[c];

  1420.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1421.                 bd.raw_other   = NULL;

  1422. 

  1423.                 if ((ret = read_block(ctx, &bd)) < 0)

  1424.                     return ret;

  1425.                 if ((ret = read_channel_data(ctx, ctx->chan_data[c], c)) < 0)

  1426.                     return ret;

  1427.             }

  1428. 

  1429.             for (c = 0; c < avctx->channels; c++) {

  1430.                 ret = revert_channel_correlation(ctx, &bd, ctx->chan_data,

  1431.                                                  reverted_channels, offset, c);

  1432.                 if (ret < 0)

  1433.                     return ret;

  1434.             }

  1435.             for (c = 0; c < avctx->channels; c++) {

  1436.                 bd.const_block = ctx->const_block + c;

  1437.                 bd.shift_lsbs  = ctx->shift_lsbs + c;

  1438.                 bd.opt_order   = ctx->opt_order + c;

  1439.                 bd.store_prev_samples = ctx->store_prev_samples + c;

  1440.                 bd.use_ltp     = ctx->use_ltp + c;

  1441.                 bd.ltp_lag     = ctx->ltp_lag + c;

  1442.                 bd.ltp_gain    = ctx->ltp_gain[c];

  1443.                 bd.lpc_cof     = ctx->lpc_cof[c];

  1444.                 bd.quant_cof   = ctx->quant_cof[c];

  1445.                 bd.raw_samples = ctx->raw_samples[c] + offset;

  1446.                 if ((ret = decode_block(ctx, &bd)) < 0)

  1447.                     return ret;

  1448.             }

  1449. 

  1450.             memset(reverted_channels, 0, avctx->channels * sizeof(*reverted_channels));

  1451.             offset      += div_blocks[b];

  1452.             bd.ra_block  = 0;

  1453.         }

  1454. 

  1455.         // store carryover raw samples

  1456.         for (c = 0; c < avctx->channels; c++)

  1457.             memmove(ctx->raw_samples[c] - sconf->max_order,

  1458.                     ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,

  1459.                     sizeof(*ctx->raw_samples[c]) * sconf->max_order);

  1460.     }

  1461. 

  1462.     // TODO: read_diff_float_data

  1463. 

  1464.     return 0;

  1465. }

  1466. 

  1467. 

  1468. /** Decode an ALS frame.

  1469.  */

  1470. static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr,

  1471.                         AVPacket *avpkt)

  1472. {

  1473.     ALSDecContext *ctx       = avctx->priv_data;

  1474.     AVFrame *frame           = data;

  1475.     ALSSpecificConfig *sconf = &ctx->sconf;

  1476.     const uint8_t *buffer    = avpkt->data;

  1477.     int buffer_size          = avpkt->size;

  1478.     int invalid_frame, ret;

  1479.     unsigned int c, sample, ra_frame, bytes_read, shift;

  1480. 

  1481.     init_get_bits(&ctx->gb, buffer, buffer_size * 8);

  1482. 

  1483.     // In the case that the distance between random access frames is set to zero

  1484.     // (sconf->ra_distance == 0) no frame is treated as a random access frame.

  1485.     // For the first frame, if prediction is used, all samples used from the

  1486.     // previous frame are assumed to be zero.

  1487.     ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);

  1488. 

  1489.     // the last frame to decode might have a different length

  1490.     if (sconf->samples != 0xFFFFFFFF)

  1491.         ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,

  1492.                                       sconf->frame_length);

  1493.     else

  1494.         ctx->cur_frame_length = sconf->frame_length;

  1495. 

  1496.     // decode the frame data

  1497.     if ((invalid_frame = read_frame_data(ctx, ra_frame)) < 0)

  1498.         av_log(ctx->avctx, AV_LOG_WARNING,

  1499.                "Reading frame data failed. Skipping RA unit.\n");

  1500. 

  1501.     ctx->frame_id++;

  1502. 

  1503.     /* get output buffer */

  1504.     frame->nb_samples = ctx->cur_frame_length;

  1505.     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {

  1506.         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");

  1507.         return ret;

  1508.     }

  1509. 

  1510.     // transform decoded frame into output format

  1511.     #define INTERLEAVE_OUTPUT(bps)                                 \

  1512.     {                                                              \

  1513.         int##bps##_t *dest = (int##bps##_t*)frame->data[0];        \

  1514.         shift = bps - ctx->avctx->bits_per_raw_sample;             \

  1515.         for (sample = 0; sample < ctx->cur_frame_length; sample++) \

  1516.             for (c = 0; c < avctx->channels; c++)                  \

  1517.                 *dest++ = ctx->raw_samples[c][sample] << shift;    \

  1518.     }

  1519. 

  1520.     if (ctx->avctx->bits_per_raw_sample <= 16) {

  1521.         INTERLEAVE_OUTPUT(16)

  1522.     } else {

  1523.         INTERLEAVE_OUTPUT(32)

  1524.     }

  1525. 

  1526.     // update CRC

  1527.     if (sconf->crc_enabled && (avctx->err_recognition & AV_EF_CRCCHECK)) {

  1528.         int swap = HAVE_BIGENDIAN != sconf->msb_first;

  1529. 

  1530.         if (ctx->avctx->bits_per_raw_sample == 24) {

  1531.             int32_t *src = (int32_t *)frame->data[0];

  1532. 

  1533.             for (sample = 0;

  1534.                  sample < ctx->cur_frame_length * avctx->channels;

  1535.                  sample++) {

  1536.                 int32_t v;

  1537. 

  1538.                 if (swap)

  1539.                     v = av_bswap32(src[sample]);

  1540.                 else

  1541.                     v = src[sample];

  1542.                 if (!HAVE_BIGENDIAN)

  1543.                     v >>= 8;

  1544. 

  1545.                 ctx->crc = av_crc(ctx->crc_table, ctx->crc, (uint8_t*)(&v), 3);

  1546.             }

  1547.         } else {

  1548.             uint8_t *crc_source;

  1549. 

  1550.             if (swap) {

  1551.                 if (ctx->avctx->bits_per_raw_sample <= 16) {

  1552.                     int16_t *src  = (int16_t*) frame->data[0];

  1553.                     int16_t *dest = (int16_t*) ctx->crc_buffer;

  1554.                     for (sample = 0;

  1555.                          sample < ctx->cur_frame_length * avctx->channels;

  1556.                          sample++)

  1557.                         *dest++ = av_bswap16(src[sample]);

  1558.                 } else {

  1559.                     ctx->bdsp.bswap_buf((uint32_t *) ctx->crc_buffer,

  1560.                                         (uint32_t *) frame->data[0],

  1561.                                         ctx->cur_frame_length * avctx->channels);

  1562.                 }

  1563.                 crc_source = ctx->crc_buffer;

  1564.             } else {

  1565.                 crc_source = frame->data[0];

  1566.             }

  1567. 

  1568.             ctx->crc = av_crc(ctx->crc_table, ctx->crc, crc_source,

  1569.                               ctx->cur_frame_length * avctx->channels *

  1570.                               av_get_bytes_per_sample(avctx->sample_fmt));

  1571.         }

  1572. 

  1573. 

  1574.         // check CRC sums if this is the last frame

  1575.         if (ctx->cur_frame_length != sconf->frame_length &&

  1576.             ctx->crc_org != ctx->crc) {

  1577.             av_log(avctx, AV_LOG_ERROR, "CRC error.\n");

  1578.             if (avctx->err_recognition & AV_EF_EXPLODE)

  1579.                 return AVERROR_INVALIDDATA;

  1580.         }

  1581.     }

  1582. 

  1583.     *got_frame_ptr = 1;

  1584. 

  1585.     bytes_read = invalid_frame ? buffer_size :

  1586.                                  (get_bits_count(&ctx->gb) + 7) >> 3;

  1587. 

  1588.     return bytes_read;

  1589. }

  1590. 

  1591. 

  1592. /** Uninitialize the ALS decoder.

  1593.  */

  1594. static av_cold int decode_end(AVCodecContext *avctx)

  1595. {

  1596.     ALSDecContext *ctx = avctx->priv_data;

  1597. 

  1598.     av_freep(&ctx->sconf.chan_pos);

  1599. 

  1600.     ff_bgmc_end(&ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1601. 

  1602.     av_freep(&ctx->const_block);

  1603.     av_freep(&ctx->shift_lsbs);

  1604.     av_freep(&ctx->opt_order);

  1605.     av_freep(&ctx->store_prev_samples);

  1606.     av_freep(&ctx->use_ltp);

  1607.     av_freep(&ctx->ltp_lag);

  1608.     av_freep(&ctx->ltp_gain);

  1609.     av_freep(&ctx->ltp_gain_buffer);

  1610.     av_freep(&ctx->quant_cof);

  1611.     av_freep(&ctx->lpc_cof);

  1612.     av_freep(&ctx->quant_cof_buffer);

  1613.     av_freep(&ctx->lpc_cof_buffer);

  1614.     av_freep(&ctx->lpc_cof_reversed_buffer);

  1615.     av_freep(&ctx->prev_raw_samples);

  1616.     av_freep(&ctx->raw_samples);

  1617.     av_freep(&ctx->raw_buffer);

  1618.     av_freep(&ctx->chan_data);

  1619.     av_freep(&ctx->chan_data_buffer);

  1620.     av_freep(&ctx->reverted_channels);

  1621.     av_freep(&ctx->crc_buffer);

  1622. 

  1623.     return 0;

  1624. }

  1625. 

  1626. 

  1627. /** Initialize the ALS decoder.

  1628.  */

  1629. static av_cold int decode_init(AVCodecContext *avctx)

  1630. {

  1631.     unsigned int c;

  1632.     unsigned int channel_size;

  1633.     int num_buffers, ret;

  1634.     ALSDecContext *ctx = avctx->priv_data;

  1635.     ALSSpecificConfig *sconf = &ctx->sconf;

  1636.     ctx->avctx = avctx;

  1637. 

  1638.     if (!avctx->extradata) {

  1639.         av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");

  1640.         return AVERROR_INVALIDDATA;

  1641.     }

  1642. 

  1643.     if ((ret = read_specific_config(ctx)) < 0) {

  1644.         av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");

  1645.         goto fail;

  1646.     }

  1647. 

  1648.     if ((ret = check_specific_config(ctx)) < 0) {

  1649.         goto fail;

  1650.     }

  1651. 

  1652.     if (sconf->bgmc) {

  1653.         ret = ff_bgmc_init(avctx, &ctx->bgmc_lut, &ctx->bgmc_lut_status);

  1654.         if (ret < 0)

  1655.             goto fail;

  1656.     }

  1657.     if (sconf->floating) {

  1658.         avctx->sample_fmt          = AV_SAMPLE_FMT_FLT;

  1659.         avctx->bits_per_raw_sample = 32;

  1660.     } else {

  1661.         avctx->sample_fmt          = sconf->resolution > 1

  1662.                                      ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;

  1663.         avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;

  1664.         if (avctx->bits_per_raw_sample > 32) {

  1665.             av_log(avctx, AV_LOG_ERROR, "Bits per raw sample %d larger than 32.\n",

  1666.                    avctx->bits_per_raw_sample);

  1667.             ret = AVERROR_INVALIDDATA;

  1668.             goto fail;

  1669.         }

  1670.     }

  1671. 

  1672.     // set maximum Rice parameter for progressive decoding based on resolution

  1673.     // This is not specified in 14496-3 but actually done by the reference

  1674.     // codec RM22 revision 2.

  1675.     ctx->s_max = sconf->resolution > 1 ? 31 : 15;

  1676. 

  1677.     // set lag value for long-term prediction

  1678.     ctx->ltp_lag_length = 8 + (avctx->sample_rate >=  96000) +

  1679.                               (avctx->sample_rate >= 192000);

  1680. 

  1681.     // allocate quantized parcor coefficient buffer

  1682.     num_buffers = sconf->mc_coding ? avctx->channels : 1;

  1683. 

  1684.     ctx->quant_cof        = av_malloc(sizeof(*ctx->quant_cof) * num_buffers);

  1685.     ctx->lpc_cof          = av_malloc(sizeof(*ctx->lpc_cof)   * num_buffers);

  1686.     ctx->quant_cof_buffer = av_malloc(sizeof(*ctx->quant_cof_buffer) *

  1687.                                       num_buffers * sconf->max_order);

  1688.     ctx->lpc_cof_buffer   = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1689.                                       num_buffers * sconf->max_order);

  1690.     ctx->lpc_cof_reversed_buffer = av_malloc(sizeof(*ctx->lpc_cof_buffer) *

  1691.                                              sconf->max_order);

  1692. 

  1693.     if (!ctx->quant_cof              || !ctx->lpc_cof        ||

  1694.         !ctx->quant_cof_buffer       || !ctx->lpc_cof_buffer ||

  1695.         !ctx->lpc_cof_reversed_buffer) {

  1696.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1697.         ret = AVERROR(ENOMEM);

  1698.         goto fail;

  1699.     }

  1700. 

  1701.     // assign quantized parcor coefficient buffers

  1702.     for (c = 0; c < num_buffers; c++) {

  1703.         ctx->quant_cof[c] = ctx->quant_cof_buffer + c * sconf->max_order;

  1704.         ctx->lpc_cof[c]   = ctx->lpc_cof_buffer   + c * sconf->max_order;

  1705.     }

  1706. 

  1707.     // allocate and assign lag and gain data buffer for ltp mode

  1708.     ctx->const_block     = av_malloc (sizeof(*ctx->const_block) * num_buffers);

  1709.     ctx->shift_lsbs      = av_malloc (sizeof(*ctx->shift_lsbs)  * num_buffers);

  1710.     ctx->opt_order       = av_malloc (sizeof(*ctx->opt_order)   * num_buffers);

  1711.     ctx->store_prev_samples = av_malloc(sizeof(*ctx->store_prev_samples) * num_buffers);

  1712.     ctx->use_ltp         = av_mallocz(sizeof(*ctx->use_ltp)  * num_buffers);

  1713.     ctx->ltp_lag         = av_malloc (sizeof(*ctx->ltp_lag)  * num_buffers);

  1714.     ctx->ltp_gain        = av_malloc (sizeof(*ctx->ltp_gain) * num_buffers);

  1715.     ctx->ltp_gain_buffer = av_malloc (sizeof(*ctx->ltp_gain_buffer) *

  1716.                                       num_buffers * 5);

  1717. 

  1718.     if (!ctx->const_block || !ctx->shift_lsbs ||

  1719.         !ctx->opt_order || !ctx->store_prev_samples ||

  1720.         !ctx->use_ltp  || !ctx->ltp_lag ||

  1721.         !ctx->ltp_gain || !ctx->ltp_gain_buffer) {

  1722.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1723.         ret = AVERROR(ENOMEM);

  1724.         goto fail;

  1725.     }

  1726. 

  1727.     for (c = 0; c < num_buffers; c++)

  1728.         ctx->ltp_gain[c] = ctx->ltp_gain_buffer + c * 5;

  1729. 

  1730.     // allocate and assign channel data buffer for mcc mode

  1731.     if (sconf->mc_coding) {

  1732.         ctx->chan_data_buffer  = av_malloc(sizeof(*ctx->chan_data_buffer) *

  1733.                                            num_buffers * num_buffers);

  1734.         ctx->chan_data         = av_malloc(sizeof(*ctx->chan_data) *

  1735.                                            num_buffers);

  1736.         ctx->reverted_channels = av_malloc(sizeof(*ctx->reverted_channels) *

  1737.                                            num_buffers);

  1738. 

  1739.         if (!ctx->chan_data_buffer || !ctx->chan_data || !ctx->reverted_channels) {

  1740.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1741.             ret = AVERROR(ENOMEM);

  1742.             goto fail;

  1743.         }

  1744. 

  1745.         for (c = 0; c < num_buffers; c++)

  1746.             ctx->chan_data[c] = ctx->chan_data_buffer + c * num_buffers;

  1747.     } else {

  1748.         ctx->chan_data         = NULL;

  1749.         ctx->chan_data_buffer  = NULL;

  1750.         ctx->reverted_channels = NULL;

  1751.     }

  1752. 

  1753.     channel_size      = sconf->frame_length + sconf->max_order;

  1754. 

  1755.     ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);

  1756.     ctx->raw_buffer       = av_mallocz(sizeof(*ctx->     raw_buffer)  * avctx->channels * channel_size);

  1757.     ctx->raw_samples      = av_malloc (sizeof(*ctx->     raw_samples) * avctx->channels);

  1758. 

  1759.     // allocate previous raw sample buffer

  1760.     if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {

  1761.         av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1762.         ret = AVERROR(ENOMEM);

  1763.         goto fail;

  1764.     }

  1765. 

  1766.     // assign raw samples buffers

  1767.     ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;

  1768.     for (c = 1; c < avctx->channels; c++)

  1769.         ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;

  1770. 

  1771.     // allocate crc buffer

  1772.     if (HAVE_BIGENDIAN != sconf->msb_first && sconf->crc_enabled &&

  1773.         (avctx->err_recognition & AV_EF_CRCCHECK)) {

  1774.         ctx->crc_buffer = av_malloc(sizeof(*ctx->crc_buffer) *

  1775.                                     ctx->cur_frame_length *

  1776.                                     avctx->channels *

  1777.                                     av_get_bytes_per_sample(avctx->sample_fmt));

  1778.         if (!ctx->crc_buffer) {

  1779.             av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");

  1780.             ret = AVERROR(ENOMEM);

  1781.             goto fail;

  1782.         }

  1783.     }

  1784. 

  1785.     ff_bswapdsp_init(&ctx->bdsp);

  1786. 

  1787.     return 0;

  1788. 

  1789. fail:

  1790.     decode_end(avctx);

  1791.     return ret;

  1792. }

  1793. 

  1794. 

  1795. /** Flush (reset) the frame ID after seeking.

  1796.  */

  1797. static av_cold void flush(AVCodecContext *avctx)

  1798. {

  1799.     ALSDecContext *ctx = avctx->priv_data;

  1800. 

  1801.     ctx->frame_id = 0;

  1802. }

  1803. 

  1804. 

  1805. AVCodec ff_als_decoder = {

  1806.     .name           = "als",

  1807.     .long_name      = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),

  1808.     .type           = AVMEDIA_TYPE_AUDIO,

  1809.     .id             = AV_CODEC_ID_MP4ALS,

  1810.     .priv_data_size = sizeof(ALSDecContext),

  1811.     .init           = decode_init,

  1812.     .close          = decode_end,

  1813.     .decode         = decode_frame,

  1814.     .flush          = flush,

  1815.     .capabilities   = AV_CODEC_CAP_SUBFRAMES | AV_CODEC_CAP_DR1,

  1816. };